Electrode system with in-band impedance detection

ABSTRACT

An apparatus comprises a headset and a control unit in communication with each other. The headset comprises a plurality of electrodes operable to measure ERP readings. The headset is configured to be positioned on a test subject. The control unit is configured to store and administer an ERP test protocol. The control unit is also configured to administer an impedance test and process the impedance of the electrodes. The impedance testing may be performed in an in-band fashion, along the same channels used to perform the ERP testing, at the same frequency of the ERP readings, and substantially simultaneously with the ERP readings.

PRIORITY

This application claims priority to U.S. Provisional Application Ser.No. 61/381,569, filed Sep. 10, 2010, entitled “Electrode System withIn-Band Impedance Detection,” the disclosure of which is incorporated byreference herein.

BACKGROUND

In some settings, it may be desirable to position a headset withelectrodes on a test subject's head, such as to test the subject forvarious conditions, including but not limited to various types ofdiseases or conditions within the cerebral cortex, Alzheimer's,Parkinson's, dyslexia, autism, and/or schizophrenia, among otherconditions. For instance, one or more system components may be used toprovide one or more types of stimuli to the test subject (e.g.,auditory, visual, and/or tactile stimulus, etc.); and electrodes may beused to detect Evoked Response Potentials (ERP's) associated with suchstimuli. By way of example only, active or locally amplified electrodes,as well as related systems and methods, are discussed in the followingdocuments, each of which is incorporated by reference herein: U.S. Pat.No. 5,479,934, entitled “EEG Headpiece with Disposable Electrodes andApparatus and System and Method for Use Therewith,” issued Jan. 2, 1996;U.S. Pub. No. 2005/0215916, entitled “Active, Multiplexed DigitalElectrodes for EEG, ECG, and EMG Applications,” published Sep. 29, 2005;U.S. Pub. No. 2007/0106169, entitled “Method and System for an AutomatedE.E.G. System for Auditory Evoked Responses,” published May 10, 2007;U.S. Pub. No. 2007/0270678, entitled “Wireless Electrode forBiopotential Measurement,” published Nov. 22, 2007; and U.S. Pub. No.2007/0191727, entitled “Evoked Response Testing System for NeurologicalDisorders,” published Aug. 16, 2007. It should be understood that theteachings herein may be applied to or otherwise combined with any of thesystems and methods taught in all of the above-cited documents. Variousways in which the teachings herein may be applied to or otherwisecombined with any of the systems and methods taught in all of theabove-cited documents will be apparent to those of ordinary skill in theart.

While a variety of systems have been made and used, it is believed thatno one prior to the inventor(s) has made or used an invention asdescribed herein.

BRIEF DESCRIPTION OF THE DRAWINGS

It is believed the present invention will be better understood from thefollowing description of certain examples taken in conjunction with theaccompanying drawings, in which like reference numerals identify thesame elements and in which:

FIG. 1 depicts a perspective view of an exemplary ERP testing system;

FIG. 2 depicts a top plan view of electrode components of the ERPtesting system of FIG. 1;

FIG. 3 depicts a rear elevational view of the electrode components ofFIG. 2;

FIG. 4 depicts a top plan view of an electrode module of the electrodecomponents of FIG. 2;

FIG. 5 depicts an exploded perspective view of the electrode module ofFIG. 4, with an exemplary sensor;

FIG. 6 depicts a top plan view of the electrode module of FIG. 4, with atop housing component and flex circuit component removed;

FIG. 7 depicts a cross-sectional side view of the electrode module ofFIG. 4, taken along line 7-7 of FIG. 4;

FIG. 8 depicts a perspective view of an exemplary sensor for use withthe ERP testing system of FIG. 1;

FIG. 9 depicts an exploded view of the sensor of FIG. 8;

FIG. 10 depicts a diagrammatic view of exemplary ERP testing system;

FIG. 11 depicts a flow chart view of an exemplary audiometry userinterface schema;

FIG. 12 depicts a diagrammatic view of a key regarding HCU statuses;

FIGS. 13A through 13B depict a flow chart view of an exemplary aspect ofHCU control logic;

FIG. 14 depicts a flow chart view of an exemplary cancellation schema;

FIG. 15 depicts a flow chart view of an exemplary measuring rest schema;

FIG. 16 depicts a flow chart view of an exemplary pre-trigger delayschema;

FIG. 17 depicts a flow chart view of an exemplary response captureschema;

FIGS. 18A through 18B depict a flow chart view of an exemplarypre-testing verification schema;

FIGS. 19A through 19B depict a flow chart view of an exemplary HCUcommunication schema;

FIG. 20 depicts a diagrammatic view of various headset states;

FIG. 21 depicts a flow chart view of an exemplary schema for exemplarycommunication checks for a headset;

FIG. 22 depicts a table view of exemplary characteristics of anexemplary session data stream;

FIG. 23 depicts a table view of exemplary characteristics of exemplaryconfiguration descriptor chunks;

FIG. 24 depicts a table view of exemplary characteristics of anexemplary epoch descriptor chunk;

FIG. 25 depicts a screen shot view of an exemplary launcher;

FIG. 26 depicts a screen shot view of an exemplary account registrationinterface form;

FIG. 27 depicts a screen shot view of an exemplary headset registrationform;

FIG. 28 depicts a screen shot view of an exemplary user registrationform;

FIG. 29 depicts a screen shot view of an exemplary patient managerpanel;

FIG. 30 depicts a screen shot view of an exemplary patent manager panelwith a test being ordered;

FIG. 31 depicts a screen shot view of an exemplary test administrationpanel;

FIG. 32 depicts a screen shot view an exemplary test administrationpanel search where orders for ERP tests are searched; and

FIG. 33 depicts a screen shot view an exemplary monitoring panel.

The drawings are not intended to be limiting in any way, and it iscontemplated that various embodiments of the invention may be carriedout in a variety of other ways, including those not necessarily depictedin the drawings. The accompanying drawings incorporated in and forming apart of the specification illustrate several aspects of the presentinvention, and together with the description serve to explain theprinciples of the invention; it being understood, however, that thisinvention is not limited to the precise arrangements shown.

DETAILED DESCRIPTION

The following description of certain examples of the invention shouldnot be used to limit the scope of the present invention. Other examples,features, aspects, embodiments, and advantages of the invention willbecome apparent to those skilled in the art from the followingdescription, which is by way of illustration, one of the best modescontemplated for carrying out the invention. As will be realized, theinvention is capable of other different and obvious aspects, all withoutdeparting from the invention. Accordingly, the drawings and descriptionsshould be regarded as illustrative in nature and not restrictive.

I. Overview of Exemplary ERP Testing System

Examples of components that may be incorporated into an ERP system areshown in FIGS. 1-9 and are described in greater detail below. Of course,an ERP system may have various other components, configurations, andoperabilities, including but not limited to any of the variouscomponents, configurations, and operabilities described in any of thevarious documents that are cited and incorporated by reference herein.

A. Exemplary System Overview

As shown in FIG. 1, an exemplary electrode system (10) includes aheadset (20) and a control box or handheld control unit (HCU) (40).Headset (20) comprises a head frame (24) and a plurality of electrodemodules (100). While headset (20) of the present example comprises eightelectrode modules (100), it should be understood that any other suitablenumber of electrode modules (100) may be used. It should also beunderstood that the arrangement of electrode modules (100) shown inFIGS. 1-3 is merely exemplary; and that electrode modules (100) may bepositioned in any other suitable arrangement. Electrode modules (100)are removably coupled with head frame (24) as will be described ingreater detail below.

B. Exemplary Head Frame

In the present example, head frame (24) is formed of several resilientstraps (26), and electrode modules (100) are secured to head frame (24)at junctions of resilient straps (26). The junctions of resilient straps(26) comprise annular snap members (28), which are each open at theircenter. As will be described in greater detail below, openings (106) ofelectrode modules (100) are configured to align with the open centers ofcorresponding snap members (28), to allow inserted sensors (200) tocontact the test subject's head. In some versions, resilient straps (26)are formed of elastic, though it should be understood that any othersuitable material or combination of materials may be used. While headframe (24) of the present example is configured to substantiallyencompass a test subject's head, it should also be understood that headframe (24) may have any other suitable configuration. By way of exampleonly, head frame (24) may comprise a EzeNet® reusable head piece byHydroDot, Inc. of Westford, Mass. A EzeNet® reusable head piece may comein various sizes and conform to the international 10/20 system ofelectrode placement.

As another merely illustrative example, head frame (24) may beconfigured and/or operable in accordance with the teachings of U.S. Pub.No. 2007/0191727, entitled “Evoked Response Testing System forNeurological Disorders,” published Aug. 16, 2007, the disclosure ofwhich is incorporated by reference herein; and/or in accordance with theteachings of any other document cited herein. Indeed, various ways inwhich the teachings herein may be combined with the teachings of U.S.Pub. No. 2007/0191727 and/or the teachings of any other document citedherein will be apparent to those of ordinary skill in the art.Alternatively, head frame (24) may have any other suitable configurationand/or operability. Other suitable variations of head frame (24) will beapparent to those of ordinary skill in the art in view of the teachingsherein.

As shown in FIGS. 1-3, electrode modules (100) are physically andcommunicatively coupled with each other via flexible connectors (50).Electrode modules (100) are also physically and communicatively coupledwith a control box interface module (30) via flexible connectors (50).Flexible connectors (50) of the present example comprise flexiblecircuits, which comprise traces (not shown) formed in a flexiblesubstrate. Alternatively, conventional wires or other conduits may beused. In the present example, headset (20) is coupled with control box(40) via cables (42). In particular, control box interface module (30)includes ports (32), with which cables (42) may be coupled. Control boxinterface module (30) also includes circuitry configured to routesignals between flexible connectors (50) and cables (42) via ports (32).Control box interface module (30) may thus provide a communicativeinterface between cables (42) and flexible connectors (50). Varioussuitable components that may be incorporated into control box interfacemodule (30), as well as various suitable features/functionalities ofsuch components, are described in the documents cited herein. By way ofexample only, control box interface module (30) may be constructed andoperable in accordance with the headset “control module 12” teachings ofU.S. Pub. No. 2007/0191727 and/or the teachings of any other documentcited herein. Still other suitable components that may be incorporatedinto control box interface module (30) will be apparent to those ofordinary skill in the art in view of the teachings herein.

In the present example, and as shown in FIG. 2, control box interfacemodule (30) also includes flanged members (34). Flange members (34) areconfigured to secure control box interface module (30) with head frame(24). For instance, head frame (24) may include openings that areconfigured to receive flanged members (34). Of course, control boxinterface module (30) may be secured to head frame (24) in a variety ofother ways as will be appreciated by those of ordinary skill in the art,to the extent that control box interface module (30) is secured to headframe (24) at all. Furthermore, control box interface module (30) maysimply be omitted in some versions (e.g., cables (42) couple directly tofreely hanging flexible connectors (50), etc.).

In some merely exemplary versions, headset (20) comprises a yoke. Such ayoke may comprise a module in headset (20) that contains second stageamplifiers, filters, one or more A/D converters, and/or audioelectronics, among other things. As one merely illustrative example, ayoke may be provided by control box interface module (30). The yoke maybe operable to provide circuit configuration for gain verification,provide circuit configuration for electrode impedance measurements,execute electrode harness error detection and reporting, and attenuateaudio. It will be appreciated that the yoke may have yoke firmwareprogrammed to perform the above listed functions. In some exemplaryversions, the yoke firmware may not be upgradeable. In other exemplaryversions the yoke firmware will be upgradeable. As a result, in theevent that the yoke firmware is upgradeable, the yoke firmware need notnecessarily be loaded prior to distribution of the yoke with control box(40). It may be upgraded after distribution. Other suitable ways inwhich a yoke may be configured and operated will be apparent to those ofordinary skill in the art in view of the teachings herein.

C. Exemplary Control Box

Control box or HCU (40) of the present example includes a storage medium(not shown) that is configured to store various testing protocols (e.g.,ERP testing protocols, etc.); and a processor (not shown) that isconfigured to execute such testing via headset (20). In particular,control box (40) provides power and commands or other types of signalsto headset (20) via cables (42) in the present example; while headset(20) transmits data or other types of signals back to control box (40)via cables (42). Control box (40) is also operable to store datacollected during such testing, including but not limited to dataobtained through electrode modules (100). Such power, commands, data, orother types of signals may be provided in accordance with various typesof ERP testing protocols as described herein and as described in thedocuments that are incorporated by reference herein.

Control box (40) is configured to be coupled with a computer system (notshown) via wire and/or wirelessly. For instance, a computer system maytransmit testing protocols, commands, or other data to control box (40).Similarly, control box (40) may transmit commands, test results, orother data to a computer system. Control box (40) of the present exampleis also configured to be handheld. By way of example only, control box(40) may be held in the hand of the test subject who is wearing headset(40), in the hand of a clinician or nurse, or in the hand of any otherperson. In addition to or in lieu of the foregoing, control box (40) maybe configured in accordance with, operable in accordance with, and/orpossess any suitable features/functionalities of similar componentsdescribed in any of the documents cited herein, including but notlimited to U.S. Pub. No. 2007/0191727. Various ways in which theteachings herein may be incorporated into or otherwise combined with theteachings of the documents that are cited herein will be readilyapparent to those of ordinary skill in the art.

While two cables (42) are shown, it should be understood that just onecable (42) may be used. It should also be understood that some otherversions of electrode system (10) may provide communication of power,commands, data, and/or other types of signals to and/or from headset(20) wirelessly, in addition to or in lieu of having cables (22).

D. Exemplary Electrode Module

In the present example, electrode modules (100) of electrode system (10)are substantially identical to each other. The following descriptionwill therefore just describe an individual electrode module (100) as anexample. It should be understood, however, that a given electrode system(10) may have different types of electrode modules (100). In otherwords, one or more electrode modules (100) within a given electrodesystem (10) may have features, components, functionalities, etc., thatdiffer from the features, components, functionalities, etc., of otherelectrode modules (100) within the same electrode system (10). Suchdifferences among electrode modules (100) may be based on a variety ofconsiderations, including but not limited to the location of electrodemodule (100) on the test subject's head or other part of the testsubject's anatomy. Suitable ways in which electrode modules (100) maydiffer from each other within a given electrode system (10) will beapparent to those of ordinary skill in the art in view of the teachingsherein. Alternatively, as in the present example, all electrode modules(100) within a given electrode system (10) may be substantiallyidentical to each other.

As shown in FIGS. 2-7, electrode module (100) comprises an upperclamshell member (102), a lower clamshell member (104), a circuit board(130), and a conductive ring (150). Clamshell members (102, 104) may beformed of molded plastic and/or using any other suitable material(s)and/or process(es). As shown, upper clamshell member (102), lowerclamshell member (104), circuit board (130), and conductive ring (150)all define a central opening (106). In particular, the central openingsof upper clamshell member (102), lower clamshell member (104), circuitboard (130), and conductive ring (150) are all configured to coaxiallyalign when these components are assembled together to form electrodemodule (100), such that the assembled electrode module (100) itselfdefines a central opening (106). This central opening (106) isconfigured to insertingly receive a sensor (200) as will be described ingreater detail below. In addition, these components are configured suchthat a portion of conductive ring (150) is exposed in the inner diameterof the central opening (106) of the assembled electrode module (100), aswill also be described in greater detail below. During assembly ofelectrode module (100), upper clamshell member (102) may be secured tolower clamshell member (104) using any suitable technique or techniques,including but not limited to ultrasonic welding, snap-fitting,adhesives, fasteners, etc. While opening (106) is at the approximatecenter of electrode module (100) in the present example, it should beunderstood that opening (106) may be located off-center or otherwiserelative to the remainder of electrode module (100).

Upper clamshell member (102) of the present example presents an annularinclined surface (108) at the perimeter of opening (106). Annularinclined surface (108) is configured to facilitate insertion of sensor(200) into opening (106) as will be described in greater detail below.Of course, as with other components and features described herein,inclined surface (108) is merely optional. Lower clamshell member (104)of the present example comprises a first pair of upwardly extendingposts (110) and a second pair of upwardly extending posts (112). Lowerclamshell member (104) also includes an annular rim (114) at theperimeter of opening (106) and a trench (116) adjacent to annular rim(114). Each of these features of lower clamshell member (104) will bedescribed in greater detail below.

Circuit board (130) of the present example comprises a pair of openings(132) and a pair of connectors (134). As shown in FIGS. 5-6, openings(132) of circuit board (130) are configured to align with and receiveposts (110) of lower clamshell member (104). Openings (132) and posts(110) may thus assist in properly registering circuit board (130) withlower clamshell member (104) and assist in securing circuit board (130)relative to lower clamshell member (104). Of course, openings (132) andposts (110) are merely one of many different ways in which circuit board(130) may be registered and secured relative to lower clamshell member(104). Various other structures, features, techniques, etc. forregistering and/or securing circuit board (130) relative to lowerclamshell member (104) will be apparent to those of ordinary skill inthe art in view of the teachings herein.

Connectors (134) of circuit board (130) are configured to be physicallyand communicatively coupled with flexible connectors (50). Inparticular, each connector (134) has a slot that is configured toreceive a free end of a corresponding flexible connector (50). Flexibleconnector (50) has an opening (52) that is configured to receive a post(112) of lower clamshell member (104). Thus, when flexible connector(50) is inserted in the slot of connector (134), with post (112)inserted through opening (52) of flexible connector (50), and whenclamshell members (102, 104) are secured relative to each other as shownin FIG. 7, the insertion of post (112) through opening (52) maysubstantially prevent flexible connector (50) from being pulled out ofconnector (134). In addition, connector (134) may have one or moreexposed/exposable electrical contacts within its slot; while the freeend of flexible connector (50) may have one or more correspondingelectrical contacts that are positioned to contact the one or moreexposed/exposable electrical contacts within the slot of connector(134). Connector (134) may thus communicate power, commands, data, othersignals, etc., to and/or from one or more traces of flexible connector(50). In some merely exemplary versions, it is contemplated thatconnectors (134), circuit board (130), flexible connector (50), and anyother suitable components may have a unitary construction such thatconnectors (134), circuit board (130), and flexible connector (50) arein continuous communication with each other. In other merely exemplaryversions, connectors (134), circuit board (130), and flexible connector(50) may be constructed from a rigid flex circuit. Other suitableconstructions will also be apparent to one of ordinary skill in the artin view of the teachings herein.

Of course, connectors (134) are merely optional, and connectors (134)may be modified, substituted, supplemented, or omitted as desired. Byway of example only, some alternative versions omit connectors (134)entirely by forming all flexible connectors (50) and circuit boards(130) as a single, unitary rigid-flex circuit. A merely illustrativeexample of such a rigid-flex circuit is disclosed in WIPO PublicationNo. 2011/0381103, entitled “Electrode System with Rigid-Flex Circuit,”filed Sep. 23, 2010, the disclosure of which is incorporated byreference herein. Still other suitable ways in which connectors (134)may be modified, substituted, supplemented, or omitted will be apparentto those of ordinary skill in the art in view of the teachings herein.

As shown in FIGS. 1-3 and as noted above, electrode modules (100) arecoupled via flexible connectors (50). In some versions, differentelectrode modules (100) have their own dedicated traces along suchflexible connectors (50). Dedicated traces for a given electrode module(100) may run along part of the same length of flexible connectors (50)as dedicated traces for another given electrode module (100). Forinstance, a set of dedicated traces for one electrode module (100) maybe provided on one layer of flexible circuitry in a given flexibleconnector (50); while a set of dedicated traces for another electrodemodule (100) may be provided on another layer of flexible circuitry onthe same flexible connector (50), with both layers extending along acommon length of the flexible circuitry of the same flexible connector(50). As another merely illustrative example, dedicated traces for oneelectrode module (100) may be provided on the same layer of flexiblecircuitry as dedicated traces for another electrode module (100), suchthat the separate sets of traces are geometrically parallel on a commonlayer. In some other versions, different electrode modules (100) mayshare one or more common traces in a given flexible connector (50). Byway of example only, one or more traces in flexible circuitry offlexible connectors (50) may be used for bus transmissions, such thatinformation associated with different electrode modules (100) may becombined onto a bus and communicated along one or more non-dedicatedtraces that are in communication with more than one electrode module(100). Various other suitable ways in which traces or othercommunication features may be used, provided, arranged, etc., will beapparent to those of ordinary skill in the art in view of the teachingsherein.

Circuit board (130) in each electrode module (100) of the presentexample also comprises sensing circuitry (not shown), which includes anamplifier among other components. Such sensing circuitry is incommunication with connectors (134) of circuit board (130), such thatthe sensing circuitry may communicate with the one or more traces offlexible connectors (50). With the sensing circuitry of circuit board(130) including an amplifier in the present example, it should beunderstood that electrode modules (100) are thus active. Such sensingcircuitry may be configured and/or operable in accordance with theteachings of U.S. Pub. No. 2005/0215916, entitled “Active, MultiplexedDigital Electrodes for EEG, ECG, and EMG Applications,” published Sep.29, 2005, the disclosure of which is incorporated by reference herein;and/or in accordance with the teachings of any other document citedherein. Indeed, various ways in which the teachings herein may becombined with the teachings of U.S. Pub. No. 2005/0215916 and/or theteachings of any other document cited herein will be apparent to thoseof ordinary skill in the art. Alternatively, the sensing circuitry ofcircuit board (130) may have any other suitable configuration and/oroperability. For instance, some versions of circuit board (130) may lackan amplifier, such that electrode modules (100) are not active. Stillother suitable ways in which circuit board (130) may be configured,including but not limited to various forms and components of sensingcircuitry, will be apparent to those of ordinary skill in the art inview of the teachings herein.

In the present example, conductive ring (150) comprises a tail portion(152) that extends radially outwardly. Conductive ring (150) isconfigured to rest on annular rim (114) of lower clamshell member (104),with tail portion (152) projecting through trench (116) of lowerclamshell member (104). Accordingly, annular rim (114), trench (116),and tail portion (152) cooperate to assist in properly registeringconductive ring (150) with lower clamshell member (104) and assist insecuring conductive ring (150) relative to lower clamshell member (104).Of course, these features are just an example, and various otherstructures, features, techniques, etc. for registering and/or securingconductive ring (150) relative to lower clamshell member (104) will beapparent to those of ordinary skill in the art in view of the teachingsherein. As best seen in FIG. 7, upper clamshell member (102) ispositionable over conductive ring (150) to further secure conductivering (150) in place by “sandwiching” conductive ring (150) betweenclamshell members (102, 104). As noted above, a portion of conductivering (150) is still exposed in the inner diameter of the central opening(106) of the assembled electrode module (100) (e.g., when upperclamshell member (102) is secured to lower clamshell member (104),etc.). Conductive ring (150) is also communicatively coupled with thesensing circuitry of circuit board (130) (e.g., through contact via tailportion (152), etc.). In particular, conductive ring (150) is configuredto communicate ERP signals to the sensing circuitry of circuit board(130) as will be described in greater detail below.

Electrode modules (100) may be coupled with head frame (24) in a varietyof ways. In the present example, electrode modules (100) are coupledwith head frame (24) through snap fittings at snap members (28) of headframe (24). For instance, as shown in FIGS. 5-7, each electrode module(100) of the present example is provided with a snap adapter (170). Eachsnap adapter (170) comprises an upper flange (172), a lower flange(174), and a cylindraceous portion (176) extending vertically betweenupper and lower flanges (172, 174). Lower clamshell member (104)includes an annular recess (118) that is configured to snappinglyreceive upper flange (172) of snap adapter (170) as shown in FIG. 7.Snap adapter (170) thus couples with electrode module (100) through asnap fitting in the present example, though it should be understood thatany other suitable features, components, techniques, etc., may be usedto secure a snap adapter (170) with an electrode module (100).Alternatively, electrode module (100) may have an integral or unitarysnap adapter, or may couple with head frame (24) in some other way.

In the present example, a pad (160) is secured to each snap adapter(170). Each pad (160) has a plurality of outwardly extending tabs (162)and is relatively soft. For instance, the configuration of pad (160) mayreduce discomfort to a test subject when a clinician manipulateselectrode modules (100) while electrode modules (100) are on the testsubject's head. Pad (160) is configured to fit about cylindraceousportion (176) of snap adapter (170). As shown in FIG. 7, pad (160) is“sandwiched” between the lower surface of lower clamshell member (104)and the upper surface of lower flange (174). Of course, pad (160) may becoupled with electrode module (100) in a variety of other ways. By wayof example only, pad (160) may be secured to electrode module by one ormore clips, hook and loop fasteners, adhesives, etc. Alternatively, pad(160) may be omitted entirely. For instance, snap member (28) of headframe (24) may be positioned about cylindraceous portion (176) of snapadapter (170). Snap member (28) may thus be “sandwiched” between thelower surface of lower clamshell member (104) and the upper surface oflower flange (174), similar to pad (160) in FIG. 7. In the presentexample, however, snap adapter (170) snappingly engages with snap member(28) (e.g., such that at least a portion of snap member (28) ispositioned below lower flange (174)).

As yet another merely illustrative variation, snap adapter (170) maysimply be omitted. By way of example only, snap member (28) may itselfsnapplingly engage with lower clamshell member (104). For instance, snapmember (28) may include an outwardly extending annular flange that issnappingly received in annular recess (188) of lower clamshell member(104). As still another merely illustrative variation, electrode modules(100) may couple directly with head frame (24), such that no snapfittings are used to couple electrode modules (100) with head frame(24). By way of example only, electrode modules (100) may be coupledwith head frame (24) by one or more clips, hook and loop fasteners,adhesives, etc. In addition, while electrode modules (100) are removablycoupled with head frame (24) in the present example, electrode modules(100) may be permanently affixed to head frame (24) in some otherversions.

It should also be understood that when several snap member (28) (orother types of electrode module (100) engagement structures) andresilient straps (26) are arranged to provide a head frame (24), somesnap members (28) may not have a corresponding electrode module (100)coupled thereto. It should therefore be understood that some headsets(20) may be configured to accommodate different kinds of electrodesystems that have different numbers of and/or arrangements of electrodemodules (100), providing a degree of modularity. Still other suitableways in which electrode modules (100) may be incorporated into a headset(20) will be apparent to those of ordinary skill in the art in view ofthe teachings herein.

E. Exemplary Sensors

As shown in FIGS. 5 and 8-9, electrode system (10) of the presentexample further includes removable sensors (200). Removable sensors(200) of this example each comprise an insulating upper portion (202),an electrolytic hydrogel lower portion (204), and a conductive centerportion (206) positioned between upper and lower portions (202, 204).Conductive center portion (206) comprises a plurality of outwardlyextending conductive tabs (156). Each sensor (200) is configured to beinserted in the central opening (106) of a corresponding electrodemodule (100) and fit snugly therein. In some settings, each electrodemodule (100) in an electrode system (10) has an associated removablesensor (200) inserted therein; though some electrode modules (100) maylack an associated electrode module (100) in some settings. Inclinedsurface (108) of upper clamshell member (102) at the perimeter ofopening (106) may facilitate insertion of sensor (200) in opening (106),such as by guiding sensor (200) into opening. Of course, as with otherfeatures described herein, inclined surface (108) is merely optional,and may be modified, substituted, supplemented, or omitted as desired.

When removable sensor (200) is inserted in electrode module (100), andthe corresponding head frame (24) is secured to a test subject's head,removable sensor (200) is configured such that electrolytic hydrogellower portion (204) contacts the scalp of the test subject. Forinstance, sensor (200) may have a height such that hydrogel lowerportion (204) protrudes below lower flange (174) of snap adapter (170)while insulating upper portion (202) is vertically positioned at or nearinclined surface (108) of upper clamshell member (102). Alternatively,sensors (200) may have any other suitable dimensions. Furthermore,depending on the positioning of a given electrode module (100), theassociated electrolytic hydrogel lower portion (204) may contact someother part of the test subject's head or body. For instance, hydrogellower portion (204) may simply contact the hair on the test subject'shead; and electrode system (10) may still work properly even if sensors(200) only contact the hair on the test subject's head withoutnecessarily contacting the skin on the test patient's scalp. Due to theelectrolytic properties of the electrolytic hydrogel lower portion(204), electrolytic hydrogel lower portion (204) may pick up voltages orsignals (e.g., ERP signals, etc.) from the test subject's (e.g.,patient's) skin. Electrolytic hydrogel lower portion (204) may collectdata without needing to be pasted or glued to the test subject's head,as the hydrogel itself may sufficiently adhere to the subject's headwhile also allowing removable sensor (200) to be pulled away from thesubject's head with relative ease.

As noted above, tabs (208) of the present example are formed as unitaryextensions of a conductive member (206) that is disposed betweeninsulating upper portion (202) and electrolytic hydrogel lower portion(204). Conductive member (206) and tabs (208) are configured such thattabs (208) are resiliently biased to assume radially outwardly extendingorientations, as shown in FIGS. 5 and 8-9. It should be understood thatwhen sensor (200) is inserted in opening (106) of electrode module(100), tabs (208) contact conductive ring (150), which is exposed in theinner diameter of opening (106) as shown in FIG. 7. For instance, tabs(208) may resiliently bear against conductive ring (150) when sensor(200) is inserted in opening (106). Such contact between tabs (208) andconductive ring (150) may provide a path for communication fromconductive member (206) to conductive ring (150) as described in greaterdetail below. In addition, elastomeric properties or other properties ofinsulating upper portion (202) and/or hydrogel lower portion (204) mayhelp retain sensor (200) in opening (106) of electrode module. Inaddition or in the alternative, sensor (200) may be oversized relativeto opening (106), such that sensor (200) is snugly or interferingly fitin opening (106). Other ways in which sensor (200) may be substantiallyretained in opening (106) will be apparent to those of ordinary skill inthe art in view of the teachings herein.

Conductive member (206) and tabs (208) may be formed of silver-silverchloride and/or any other suitable material or materials. Conductivering (150) may also be formed of silver-silver chloride and/or any othersuitable material or materials. With conductive member (206) and tabs(208) being in direct contact with electrolytic hydrogel lower portion(204), it should be understood that voltages or signals that are pickedup by electrolytic hydrogel lower portion (204) may be furthercommunicated to and through tabs (208). With tabs (208) being in contactwith conductive ring (150) when sensor (100) is inserted in opening(106) of electrode module (100), tabs (208) may thus communicatevoltages or signals picked up by electrolytic hydrogel lower portion(204) to conductive ring (150), which may in turn communicate suchvoltages or signals to sensing circuitry of circuit board (130). Anamplifier on circuit board (130) (or elsewhere) may amplify the signal,and other components within the sensing circuitry may perform otherprocessing of the signal if desired, and the signal may then becommunicated away from electrode module (100) via flexible circuitry inone or more flexible connectors (50). The signals may thus ultimately becommunicated to control box interface module (30) via flexibleconnectors (50) and then on to control box (40) via cable (42).

In some versions, removable sensors (200) comprise HydroDot® DisposableEEG Electrodes or HydroDot® Biosensors by HydroDot, Inc. of Westford,Mass. Various aspects of the HydroDot® Disposable EEG ElectrodeApplication System are discussed in U.S. Pat. No. 5,479,934, entitled“EEG Headpiece with Disposable Electrodes and Apparatus and System andMethod for Use Therewith,” issued Jan. 2, 1996, which is incorporated byreference herein. Of course, various components of electrode system(10), including but not limited to removable sensors (200), may beconfigured, modified, and/or operable in accordance with any suitableteachings in U.S. Pat. No. 5,479,934. Indeed, various ways in which theteachings herein may be combined with the teachings of U.S. Pat. No.5,479,934 will be apparent to those of ordinary skill in the art. Itshould also be understood that removable sensors (200) are notnecessarily required in all versions. For instance, electrode modules(100) may be configured such that they have an electrical interface withthe test subject's head and/or some other type of interface with thetest subject's head and/or other body part through an injectable gel orin any other suitable fashion.

While sensors (200) of the present example have a substantiallycylindraceous shape, it should be understood that sensors (200) mayalternatively have any other shape. By way of example only, sensors(200) may have a cubical shape, a right cuboidal shape, a conical shape,a frustoconical shape, a pyramidal shape, a spherical shape, and/or anyother suitable shape. Similarly, while conductive rings (150) of thepresent example have a substantially circular shape, it should beunderstood that conductive rings (150) may alternatively have any othershape. By way of example only, conductive rings (150) may have a squareshape, a rectangular shape, a triangular shape, and/or any othersuitable shape. Still other suitable configurations of and relationshipsbetween sensors (200) and conductive rings (150) will be apparent tothose of ordinary skill in the art in view of the teachings herein.

In the present example, electrode system (10) comprises eight electrodemodules (100). As another merely illustrative example, electrode system(10) may comprise twenty three electrode modules (100). Of course,electrode system (10) may alternatively comprise any other suitablenumber of electrode modules (100). It should also be understood thatelectrode modules (100) may be arranged in a variety of ways. By way ofexample only, various suitable arrangements are disclosed in thedocuments that are cited herein.

Signals obtained using electrode system (10) may be processed inaccordance with the teachings of U.S. Pub. No. 2008/0208072, entitled“Biopotential Waveform Data Fusion Analysis and Classification Method,”published Aug. 28, 2008, the disclosure of which is incorporated byreference herein. Alternatively, signals obtained using electrode system(10) may be processed in any other suitable fashion. In addition,various suitable ways in which electrode system (10) may be used(including but not limited to signal processing) are disclosed in thevarious documents cited herein. Still other suitable ways in whichelectrode system (10) may be used will be apparent to those of ordinaryskill in the art in view of the teachings herein. It is contemplatedthat the teachings herein may be incorporated into or otherwise combinedwith the systems, components, and methods disclosed in the documentscited herein, in numerous ways. Suitable ways in which the teachingsherein may be incorporated into or otherwise combined with the teachingsof the documents cited herein will be apparent to those of ordinaryskill in the art in view of the teachings herein.

II. Exemplary ERP Testing System

FIG. 10 shows an exemplary ERP system (500) comprising an exemplaryelectrode system (10) as shown in FIGS. 1-9 in communication with alauncher (300), a database (310), a classifier (320), and a viewer(330). It will be appreciated that ERP system (500) will have variousfeatures that may all be included in ERP system (500). In otherinstances, only some of the features may be included. Generally, ERPsystem (500) includes a software application (510) for use with headset(20), which will be described in further detail below and is incommunication with launcher (300), database (310), classifier (320), andviewer (330). To that end, the software application (510) may be aclient or a server application used to create and administer newaccounts, users, groups, and headsets (20) in connection with ERPtesting. Furthermore, ERP system (500) is operable to create and storetest protocols using high-level, paradigm-specific parameters. Softwareapplication (510) of ERP system (500) is operable to store patient data,which will be discussed in more detail below. Software application (510)of ERP system (500) may also be used at or in conjunction with a testingclinic to administer test protocols using the high-level,paradigm-specific parameters discussed above. ERP system (500) mayutilize a control box (40), as seen in FIG. 1, to administer a desiredtest where control box (40) has a test protocol installed. In theexemplary version, control box (40) comprises a handheld control unit(HCU), but any suitable form factor for control box (40) may be used aswould be apparent to one of ordinary skill in the art in view of theteachings herein. Once test protocols are carried out, softwareapplication (510) of ERP system (500) allows users to view and analyzethe results of an ERP test and may also be used with a computer (511) toview and analyze results.

As stated above, ERP system (500) includes software application (510)operable to create and administer new accounts, users, groups, andheadsets (20). It will be appreciated that as users and accounts arecreated in software application (510), users may be able to have morethan one account on the application. The users and/or accounts may becontrolled such that specific account users or accounts have accesslimited to other applications or data. Furthermore, users and/oraccounts on software application (510) may be organized into groupsoperable to facilitate sharing of ERP test protocols, testconfigurations, test data, and other anonymous patient data. Headsets(20) may also be used in conjunction with software application (510) toregister, detect, self-test, or reorder headsets (20).

As also stated above, ERP system (500) includes software application(510) operable to create and store test protocols using high-level,paradigm-specific parameters. In particular, ERP system (500) issufficient to carry out a complete set of predefined tests during asingle testing session. In order to do so, it will be appreciated thatthe test protocol stored on control box (40) contains a complete set ofERP paradigm descriptions, a sufficient set of control parameters,control logic, and other necessary information for control box (40) torun a complete set of predefined tests. ERP system (500) is furtherhighly customizable. The user may define tests to be performed by ERPsystem (500) during a single session. Furthermore, since some of thetests carried out by ERP system (500) include audio stimulus, ERP system(500) is operable to perform an audiometry test prior to theadministration of ERP tests.

The user is also able to define test configurations for ERP system(500). The user may determine various thresholds for ERP system (500)including a resting threshold for the peak-to-peak threshold of when atest should begin as well as a duration for said resting threshold whichdetermines the duration for which the resting threshold must be below inorder to begin a test. Additionally, the user is able to select from apredefined set of ERP paradigms to prompt the user to select and/ordefine various paradigm testing parameters. Thereafter, ERP system (500)is operable to create stimulus sequence data which conforms to theparadigms and parameters selected by the user. In relation to controlbox (40), the user may also specify whether button presses of controlbox (40) should be captured. Further, to the extent that a computer isused to perform the tests, the user may also define whether instructionsare displayed on the computer during the administration of the test inaddition to the particular message itself shown by the computer. Theuser may also specify range of delays in timing between stimulipresented by ERP system (500). ERP system (500) may consequently createthe required list of randomized value within the range provided by theuser. The user will also be able to specify the electrodes (quantity inaddition to which particular electrodes) as well as the duration forcapturing data, which will be used to determine how test data may becaptured. In the event that the user wishes to specify the particularstimuli to be used, ERP system (500) is operable to allow the user todesignate his or her own stimuli. It will be appreciated that the customstimuli may include auditory, visual, or somatosensory stimulus. It willbe understood that visual stimuli can include those presented from apoint light source, matrix display, or any other suitable visual displaydevice as would be apparent to one of ordinary skill in the art in viewof the teachings herein. The user may also be able to customize the wayin which the stimuli is presented. For example, the stimuli may bepresented to the right side, left side, both sides, or alternatingly tothe right side and left side of the eyes for visual stimuli and ears forauditory stimuli. The user may also determine parameters regarding theconclusion of the ERP test. For example, the user may specify a maximumtotal test duration which may be used to set a duration, which whenexceeded, ends the test. The user may also set the maximum artifactthreshold errors. As a result, when the number of recorded EEG valuesexceeds a defined threshold, which may result in an error, the testterminates. Finally, the user may specify a maximum resting durationtest, which results in terminating the test if the EEG values do notexceed a particular threshold for the specified duration, thusindicating that the subject is not sufficiently relaxed for the test.

ERP system (500) also allows the user to select parameters regardingmeasuring skin-contact impedance. In particular, the user may specify athreshold impedance measurement, which when exceeded, will cause ERPsystem (500) to pause testing. ERP system (500) may further be operableto display which electrode (if any) exceeds the threshold impedancemeasurement. In some exemplary versions, an audio indicator may be usedinstead of a display to convey electrode information. Additionally, ERPsystem (500) may be operable to reset the ERP test in the event that theuser defined threshold impedance is exceeded.

ERP system (500) may receive a variety of user defined parameters toform a single test protocol, but it will be further appreciated that ERPsystem (500) may include several test protocols as a result of the userdefining parameters in several ways for different test protocols.Furthermore, ERP system (500) may include test protocols havingparameters not defined by the user or any combination of user definedtest protocols as well as non-user defined test protocols.

Prior to the administration of any test protocols that involve auditorystimuli, ERP system (500) may be operable to test the subject's hearingto determine whether the volume of any auditory stimulus should beadjusted prior to administering the test using, for example, anamplifier or an attenuator, as appropriate. Furthermore, the specificauditory needs of a subject may be stored such that further testsadministered to the same subject will incorporate the same volumeadjustment. ERP system (500) is operable to test the subject's hearingat a variety of frequencies as it will be understood that the volumeadjustment of any auditory stimuli given by ERP system (500) may befrequency dependent. In some instances, rather than automaticallyadjusting the volume of auditory stimuli based on hearing tests of thesubject, the user may simply manually adjust the auditory stimuli to aparticular frequency by setting the deficit level of the subject at aparticular frequency. In some other exemplary instances, the user mayset multiple deficit levels for several frequencies. A deficit level issimply an adjustment that may be made to enable a subject to hear audioat appropriate levels.

Software application (510) of ERP system (500) may be operable to storeinformation regarding a test subject including, but not limited to,personal information, medical information, and biomarker information. Asa result, when a subject returns for subsequent visits, the user or aphysician may be able to select the profile of the subject as well asthe test protocol previously performed on the subject. Thus, the sametest protocol previously performed may be ordered again for the subject.Of course, in some exemplary instances, the test protocol may bechanged. In the event that a test subject is located remotely inrelation to the physician, the physician may also select that a testprotocol for the subject should be administered remotely.

In the present exemplary version, software application (510) comprises aclient application, which may be used with control box (40); or may beused with computer (511) proximate to the subject, control box (40), andexemplary electrode system (10). Software application (510) may furtherhave a variety of functionalities in relation to headset (20), as shownin FIG. 1. For example, software application (510) may be operable towirelessly pair control box (40) with headset (20). The wirelessconnection may be achieved through Bluetooth, wifi, or any othersuitable wireless connection system as would be apparent to one ofordinary skill in the art in view of the teachings herein. In doing so,software application (510) may attempt to connect to the most recentlyconnected headset (20). In the alternative, software application (510)may perform a scan of available wireless devices and determine whichdevices are compatible with ERP system (500). Software application (510)would then verify proper ownership of headsets (20). The physician oruser may also be able to select a particular headset (20), for example,from a list of headsets (20) shown by software application (510). ERPsystem (500) may then connect to the particular headset (20), perform aself test on headset (20), and detect the battery level of headset (20).Furthermore, the firmware version of headset (20) may be detected andchecked to determine if the most updated firmware is installed onheadset (20). In the event that a more updated firmware version isavailable, software application (510) may be operable to deliver theupdated firmware to headset (20) for upgrading. Software application(510) may further be operable to check if data exists from previous testprotocols exists on headset (20), and if so, may prompt the user toupload the data, or in the alternative may simply automatically retrievethe data. Furthermore, software application (510) is operable toidentify previously ordered test protocols and wirelessly download testprotocols for a selected patient/subject. Software application (510) mayalso display previously defined button instructions. Softwareapplication (510), upon initiation of a test protocol, is operable todisplay all test data, test message, impedance information, buttonresponse, test status, or any other suitable information as would beapparent to one of ordinary skill in the art in view of the teachingsherein. Once the test protocol is complete, software application (510)may be operable to upload the test data to the server.

In some exemplary versions, there may also be various checks orverification systems to ensure proper operation of ERP system (500). Forexample, software application may be operable to prevent a test protocolfrom being executed if a charger for headset (20) is plugged in toreduce the possibility of shock. In some versions, software application(510) is operable to prompt the user if it is safe to physicallyposition headset (20) on a subject. Software application (510), asstated above, may be operable to determine if an audiometry test isneeded, and if so, may be operable to perform the test. Softwareapplication (510) may also be operable to execute real-time, in-band,skin contact impedance measurement which enables ERP system (500) tomeasure in-band impedance, which will be described in further detailbelow, and which may be used as a baseline for further impedancemeasurements performed between consecutive epoch sets of the test. Afurther check may be operable to determine if EEG values are readingbelow a resting threshold for a specified duration prior to beginningthe administration of the test. Software application (510) may also beoperable to output to a display to the user the real-time status of thetest protocol, including information regarding which test stimulus isbeing administered. Additionally, software application (510) may beoperable to detect and analyze EEG artifacts detected by control box(40). If such artifacts may potentially cause issues with the testprotocol or software application (510), the test may be terminated.Software application (510) may be operable to prevent more than one testprotocol from being simultaneously executed

In the event that a test protocol is running and headset (20) becomesinadvertently decoupled with a client computer or other hardware piececoupled with wirelessly connected headset (20), software application isoperable to attempt to reestablish connection. It will be appreciated,however, that a continuous connection is not necessary for performing asuccessful test protocol. Test protocol and headset (20) may be operableto execute a test protocol despite being disconnected inadvertently.Control box (40) may be operable to terminate or halt operation inseveral scenarios that may prevent control box (40) from optimallyperforming including if control box (40) is out of memory, if controlbox (40) or headset (20) runs out of, or is in danger of running out ofbattery power, if the test time has exceeded a preset test durationparameter, if a maximum number of errors has been reached, or if theuser and/or physician simply terminates the test. After the completionof the test, control box (40) and/or headset (20) is operable to storetest data. To the extent that the subject has an online record, whichmay be stored, for example, in database (310), the data collected whileperforming test protocols may be uploaded to database (310). Onceuploaded, in some exemplary versions, control box (40) may then deletepatient/subject data. Finally, once data has been collected, data may beviewed using software application (510), and for example, a display incommunication with software application (510) where software application(510) is operable to apply various preprocessing parameters includingnormalization (e.g., peak to peak, RMS, drift, offset, etc.), artifactexclusion (e.g., standard minimum deviation, repeated values, medianoutliers, max peak to peak, relative amplitude, etc.), epoch groupingusing ERP test configuration logic, and automatic averaging using ERPtest configuration logic (linear and nonlinear). It will be understoodthat software application (510) may also be operable to show grandaverages from ERP test data collected using the same ERP testconfiguration in a linear or nonlinear manner.

III. Exemplary Audiometry User Interface Schema

In some versions, and as described elsewhere herein, ERP system (500)performs an audiometry test on the test subject before performing an ERPtest (e.g., to adjust to a per-patient customized volume for use duringthe ERP test, etc.). For instance, such an audiometry test may be usedto detect the hearing capabilities of the test subject, such that soundlevels used during the ERP test may be adjusted accordingly. In somecases, if the subject has trouble hearing, then the audio stimuli of ERPsystem (500) may have its volume increased.

FIG. 11 shows an exemplary audiometry user interface schema (450) for atest subject. It will be appreciated that audiometry user interfaceschema (450) is operable to determine generally the threshold hearinglevel of a subject. At block (400), the audiometry test begins followedby outputting an audio tone at block (402). In the present example, theaudio tone is a 40 dB tone having a 1000 Hz frequency, but it will beappreciated that any suitable audio tone may be used as would beapparent to one of ordinary skill in the art in view of the teachingsherein. Furthermore, it will be appreciated that multiple differenttones may be used set at different frequencies and at different volumelevels. Additionally, audio tones may be applied to the left ear of thesubject or the right ear. The duration of the audio tone in the presentexample may last 3 seconds, but any suitable duration for the audio tonemay be used as would be apparent to one of ordinary skill in the art inview of the teachings herein. In some exemplary versions, the audio toneis played first in one ear (i.e.—left ear) and then a short pause isprovided to allow the subject to respond to verify whether the subjectcan hear the audio tone. Then, the audio tone is played in the otherear, again stopping to determine whether the subject can hear the tone.While the initial tone is 40 dB, block (406) checks whether the volumeof the adjusted audio tone is equal to 80 dB or 0 dB. If either 80 dB or0 dB is the volume, then block (410) tells audiometry user interfaceschema (450) to return, ending the schema.

If the audio tone is neither 80 dB nor 0 dB, then block (408) presents adelay followed by presenting the tone. As stated above, the audio toneis initially 40 dB, but may be adjusted as follows: block (412) askswhether the subject responds. If so, block (414) asks whether thesubject responds after hearing the audio tone at ⅔ of its current audiolevel. If so, then block (410) tells audiometry user interface toreturn, ending the schema. If not, then the audio tone is decreased by10 dB before returning to block (404). If, however, at block (412) thereis no response, then block (416) increases the audio tone by 5 dB beforereturning to block (404). Of course, while the exemplary versionincreases and decreases the volume of the audio tone by 5 dB and 10 dB,respectively, it will be appreciated that any suitable increase ordecrease may be used as would be apparent to one of ordinary skill inthe art in view of the teachings herein. Ultimately, the schema endswhen the audio tone reaches 80 dB (the loudest tone that may beproduced) or 0 dB (no tone being produced) or when the subject is ableto hear the audio tone at its current level as well as at ⅔ of itscurrent level.

Various other suitable ways in which audiometry may be provided will beapparent to those of ordinary skill in the art in view of the teachingsherein. In some versions, the ERP system (500) does not perform anaudiometry test, and simply executes an ERP test.

IV. Exemplary HCU Control Logic

As described elsewhere herein, ERP system (500) includes a handheldcontrol box or HCU (40). As also noted herein, HCU (40) may includehardware configured to store and execute ERP testing protocols and storeresults, such that an entire ERP test may be run solely with HCU (40)and headset (20). HCU (40) may be paired with computer (511) to receivetesting protocols for storage and later execution; and to transmit testresults. In some versions, HCU (40) communicates with a client computer(511) wirelessly via the Bluetooth protocol, though it should beunderstood that any other suitable protocol (e.g., non-Bluetooth RFcommunication) and/or any other suitable modality (e.g., wiredcommunication, etc.) may be used.

FIG. 12 shows a key (600) for indicating HCU (40) states which is usedto indicate the various states of HCU (40) throughout FIGS. 13-19. State0 (602) indicates that HCU (40) power is off or otherwise in a low powerstate. State 1 (604) is used to indicate that the power of HCU (40) isin an “on” state with no test in the memory. Furthermore, state 1 (604)is operable to receive command code. State 2 (606) represents that HCU(40) is in a data sampling state. State 3 (608) is used to indicate thatHCU (40) is in either a cancel, program interrupt, reset, or return toready state. State 4 (610) is used to indicate that HCU (40) is in anactive and operating state. State 5 (612) is used to indicate that HCU(40) is waiting for session data stream (SDS) upload or to cancel thetest. State 6 (614) is used to indicate that HCU (40) is currentlypaired using Bluetooth or USB pairing.

FIGS. 13A-13B show an exemplary aspect of HCU Control Logic. Inparticular, it shows an initialization sequence (700). Block (702)involves turning on HCU (40). Block (704) shows power up of peripherals.Block (710) shows that the status of HCU (40) is that there is no testprotocol currently on HCU (40) and that the battery of HCU (40) is full.In the event that the user wishes to turn off HCU (40) after powering upperipherals, block (721) shows the user holding the on/off switch whichleads to block (723) where turning off of the device is communicated tothe user. Module (706) show HCU (40) making a hardware connection viaBluetooth pairing and USB pairing. In the exemplary version, in theevent that Bluetooth pairing is achieved, HCU (40) may be operable tosend a state command regarding the pairing state of HCU (40). In theevent that USB pairing is achieved, Bluetooth will become disabled, andin the event that USB pairing drops, Bluetooth pairing will be reenabledsuch that HCU (40) and headset (20) or computer (511) remain in a pairedstate as shown in block (716). Blocks (708) shows that HCU (40) mayreceive a command or act on a command and then return HCU (40) to state1 (604). Block (712) shows the user pressing a button to download a testprotocol. It will be appreciated that the button could comprise a hardphysical button or in the alternative could comprise a software button.Thereafter, block (714) asks whether data storage of HCU (40) is full ornot. In the event that HCU (40) is full, block (718) prompts an inputfrom the user as seen in block (719), which displays a message to theuser stating that memory is full and requesting the user to press aconfirmation key. The user at block (720) presses “yes,” which returnsHCU (40) to state 1 (604). In the event that the data storage on HCU(40) is not full, then block (722) shows receiving Session StartupStream (SSS), from for example, a host computer (511), which will bedescribed in further detail below. Block (724) shows HCU (40) receivingaudio. Block (726) verifies whether the charger is plugged in. If so,then block (728) communicates a message directing charger to be removed.Once the charger is unplugged, then block (730) sends Session MonitoringStream (SMS) from HCU (40) to the host computer (511). Furthermore, HCU(40) status is set to status 3 (608), and block (729) communicates tothe user that the status is ready and communicates the state of thebattery. Block (734) shows waiting for input, after which the user maypress Enter (736) to cause several tests to begin at block (740). Block(744) sends SMS and block (746) communicates to the user that test is inprogress. Block (742) checks whether an audiometry flag is set todetermine if an audiometry test should be performed. If the flag is set,then block (758) directs audiometry test to be performed as shown inFIG. 11. Block (760) determines whether the audiometry test issuccessful. If so, then block (748) checks if impedance flag is set. Ifnot, then block (762) marks test complete. If impedance flag is set,then block (750) performs baseline impedance measurements, which will bediscussed in more detail below. Thereafter, block (754) sends SMS andblock (752) takes baseline impedance. Once baseline impedancemeasurements are complete or if block (748) determines impedance flagwas set to “no,” then block (756) directs HCU (40) to change tomeasuring rest state. Block (764) begins sample data sequence shown inFIG. 14.

It will be understood that during the course of using HCU (40), the usermay wish to cancel a current sequence or otherwise halt the operation ofHCU (40). FIG. 14 shows an exemplary cancellation schema starting atblock (764). Block (766) determines whether user cancels test. If usercancels test, then module (768) is executed including in block (770) theuser pressing or holding a cancel and/or back button. Block (772) thensends SMS while block (774) communicates to user that the test wascancelled and prompting the user to press yes and/or confirm. The userconfirms as shown in block (776) where thereafter HCU (40) is in state 3(608).

FIG. 15 depicts an exemplary measuring rest schema starting at block(778) to begin the schema. It will be appreciated that the rest schemamay be operable to determine if the subject is sufficiently relaxed totake the ERP test. Block (782) sends SMS from headset (20) to HCU (40).Block (780) indicates to the user that HCU (40) is waiting for a restingEEG. Block (784) determines whether a maximum resting EEG threshold isexceeded over a set duration. In the instance that it is, block (786)sends SMS from HCU (40) to the host computer (511) and block (788)communicates to the user that the patient is restless and directs theuser to press “yes” or another suitable confirmation button. Thereafter,block (790) ends the test, since it has been determined that the patientis too restless to take the ERP test. In the event that the maxthreshold duration was not exceeded, block (792) determines whetherenough samples were taken below the threshold duration. Block (794) setsHCU (40) to a pre-triggered state if enough samples were taken. If not,then HCU (40) returns to status 2 (606). After changing to a pre-triggerstate, block (796) begins a pre-trigger delay schema.

FIG. 16 shows an exemplary pre-trigger delay schema starting at block(796). Block (798) determines if any artifacts have been detected. Ifso, then block (800) sets an artifact flag. If an artifact has not beendetected, then the block (802) writes a sample reading to FLASH RAM. Itwill be appreciated that other memories may be used such as other solidstate types of memory, a hard drive, or any suitable memory that wouldbe apparent to one of ordinary skill in the art in view of the teachingsherein. Block (804) sends SMS. Block (806) determines if pre-triggerdelay is elapsed. If so, then block (808) begins playing an audiostimulus. Block (810) then sends SMS from HCU (40) to the host computer(511). Block (814) indicates that an audio stimulus is being played forthe user. It will further explain what audio stimulus is being played.Block (812) changes HCU (40) to response capture state. Block (816) thenleads to response capture schema shown in FIG. 17 while the status ofHCU (40) is set to status 2 (606).

FIG. 17 shows the response capture schema starting at block (816). Block(818) checks if an artifact has been detected, and if so, block (820)sets an artifact flag. Thereafter, block (824) detects if button test issatisfied. If so, then block (822) stops checking buttons and labelepoch. Then, block (826) writes a sample to FLASH RAM. Of course, othersuitable memory types may be used as would be apparent to one ofordinary skill in the art in view of the teachings herein. Block (828)then sends SMS from HCU (40) to the host computer (511). Block (830)determines if the response capture duration has elapsed. If the responsecapture duration has elapsed, then block (832) changes HCU (40) to thenull-action duration state, which begins at block (834).

The schema shown in FIGS. 18A-18B begins at block (834) with the nullaction duration determining at block (838) whether HCU (40) is out ofmemory. If so, then the SMS will be sent to the host computer (511) atblock (840) and a message stating the out of memory error at block (836)will be shown with a prompt for the user to select “yes” or some otherform of confirmation. Block (842) shows that the out of memory test ascomplete. Block (844) then determines if the maximum configuration timehas been exceeded. If so, then the SMS will be sent to, for example, thehost computer (511), and a message at block (846) states that the testtime is up. After the user acknowledges that the test time is up, thenblock (850) verifies that the test is complete. Block (852) determineswhether the battery is OK, which may check for battery capacity, batterywear, or any other suitable diagnostic indicator. If there is an issuewith the battery, then SMS is sent at block (856) communicating that thebattery is low in block (854). Thereafter, the battery test is markedcomplete at block (858). Block (860) includes an artifact test todetermine if any artifact errors occurred in epoch, where in “epoch”simply means during the test. If so, then block (864) determines whethera maximum number of errors has been exceeded. If the number has beenexceeded, block (872) sends SMS to the host computer (511) and thenmarks the artifact error test complete at block (872) after displayingto user that the maximum number of artifact errors have been reached atblock (870). If the maximum number of errors has not been reached, theblock (862) finalizes an epoch descriptor chunk and then sends SMS atblock (868). Block (870) indicates to the user that maximum number oferrors have been reached. Block (882) determines if an error reset flaghas been set, followed by block (878) to change HCU (40) to themeasuring rest state if the error reset flag has been set and changingHCU (40) to the pre-trigger delay state if the errors reset flag has notbeen set. In either case, block (880) rewinds to the beginning of theepoch set and sets HCU (40) status to state 2 (606).

After the various tests have been complete, block (890) begins to sampleimpedance. Block (892) checks if an impedance threshold has been set.Block (894) determines if an impedance error has occurred. Block (896)determines if a maximum number of errors have been exceeded. If not,then block (898) sends SMS. Block (900) again sends SMS and block (902)displays check message and prompts the user to confirm while at block(904), user input is waited on. Thereafter, block (906) may begin acancel monitor sequence or if the user confirms at block (886), then atblock (882), errors reset flag set check is run. If the impedancethreshold is not set, then block (908) sends SMS, and then block (910)finalizes epoch descriptor chunk. Block (912) waits for a duration ofnull-action to complete and block (914) determines if epoch isremaining. If not, then block (916) finalizes configuration descriptorchunk. Thereafter, block (918) determines if there are configurationsteps remaining. If not, then block (930) designates the test beingcomplete. If configuration steps remain, then block (920) waits forinter-configuration delay. From there, block (922) communicates that anew configuration is loading and block (924) loads a new configuration.Block (926) then sets HCU (40) to measuring rest and the measure reststeps are taken at block (928). In the event that HCU (40) determinesthat there is epoch remaining at block (914), then block (932)determines if resting threshold reset flag is set. If so, then block(934) is set to measuring rest and will perform the measuring restschema indicated by block (938). If the resting threshold reset flag isnot set, then block (936) is set to pre-trigger delay (936) andpre-trigger delay schema may be performed at block (940).

FIG. 19A-19B show from block (930) where the test is complete. The testmay include any of the various tests mentioned above. Block (942)finalizes Session Descriptor Stream (SDS). From there, block (946) mayinitiate the cancel monitor sequence. Block (948) sends SMS while block(944) displays that test has been completed and that data may be or iscurrently uploading. Block (948) accepts an input to then send SMS atblock (960). Block (950) prompts and initiates a command to uploadresults to HCU (40) followed by block (954) which sends SMS. Block (952)communicates to the user that data is being uploaded and informs theuser to wait. Block (956) uploads data to a server from HCU (40) andonce it has been confirmed that the data has been uploaded, then sends acommand to erase SSS/SDS to HCU (40). Block (961) accepts confirmationfrom the user followed by sending SMS at block (960) and displaying amessage at (950) informing the user that the status is that the data isready and further informing user of the state of the battery. Block(962) performs pairing and block (964) verifies that the user is ready.Block (978) displays SMS and test data. Block (966) determines if theuser is ready followed by block (968) where Device Status Stream (DSS)is sent. From there, various options may be executed including donothing (970), switching to monitor tabs (972), disable “upload results”button, delete GUID, switch to testing tab (974), switch to monitor tab,or enable upload results button (976). Block (982) is where the user maypress upload results to HCU (40) and/or a computer (511), followed byblock (986) sending SMS and block (984) displaying that data is beinguploaded. At block (988) upload is pending and block (990) performsupload of data to server, where upon confirmation of the upload, an“erase SSS/SDS” command is sent to HCU (40).

Block (992) shows a cancel monitor schema where block (994) asks whetherthe headset (20) is pairing. If so, block (996) determines whether datais being received. If so, then block (998) displays SMS. If data is notbeing received, then block (1000) determines whether the user is ready.Thereafter, block (1002) sends DSS resulting in any of block (1004),block (1006), block (1008), or block (1010), where block (1004) includesdoing nothing, block (1006) includes switch to monitor tab, block (1008)includes disabling upload results button, deleting GUID, and switchingto testing tab, and block (1010) includes switch to monitor tab andenabling upload results button.

Other suitable control logic aspects will be apparent to those ofordinary skill in the art in view of the teachings herein.

V. Exemplary System Control Logic

An exemplary system control logic is described with particular referenceto headset (20) of ERP system (500). In particular, FIG. 20 shows thevarious available states for headset (20) and how they may relate in adiagrammatic form. It will be appreciated that headset (20) may assume aready state (2008) where headset (20) has no commands provided, or mayhave a reset command, a stop command, and/or an are you ready command.Headset (20) may be operable to assume a receive stream state (2002) asa result of headset (20) being instructed to receive a stream fromelectrodes (10). Headset (20) remains in receive stream state (2002) solong as data on any data bus between electrodes (10) and headset (20) orbetween headset (20) and HCU (40) remains. Headset (20) may transitionfrom receive stream (2002) state to ready state (2008) once a totalnumber of predetermined bytes are received. Headset (20) may furtherassume a wait state (2004) as a result of simply no data being availableon the bus of headset (20). Wait state (2004) may remain until headset(20) has no data contained. Headset (20) may also assume a send streamstate (2006) as a result of headset (20) receiving instructions to senda data stream to HCU (40). Send stream state (2006) may remain whiledata remains to be sent. Headset (20) may then transition from sendstream state (2006) to ready state (2008) when a stop and/or resetcommand is provided or if no more data is available. Headset (20) mayalso assume a wait for patient ID state (2010) as a result of headset(20) being disconnected from a USB connection. Headset (20) may returnfrom wait for patient ID state (2010) to ready state (2008) by headset(20) being connected via USB connection. Finally, headset (20) maytransition from wait for patient ID state (2010) to testing state (2012)as a result of input of a patient ID and may transition from testingstate (2012) to wait for patient ID state (2010) by the completion of anERP test.

It will be appreciated that it may be desirable to monitor the readystate of headset (20). To the extent that a connection with headset (20)is not constant, the integrity of the data received from headset (20)may be at risk. To that end, FIG. 21 depicts various communicationguidelines regarding headset (20) ready state to verify that headset(20) is ready for use. Block (3000) sends an “are you ready” command todetermine status of headset (20). If headset (20) is ready, then block(3020) directs that host, such as HCU (40), to issue, send or receivecommands to headset (20). Block (3004) issues a stop command from HCU(40) if headset (20) is not ready. At block (3006), HCU (40) againqueries headset (20) to ask if headset (20) is ready. Block (3008) askswhether headset (20) is ready. If too much time elapses, then block(3010) directs that HCU (40) waits for timeout code. Block (3014) askswhether timeout code is received within 3-4 seconds. If so, then block(3012) again asks if headset (20) is ready. At block (3016), HCU (40)tries to determine if headset (20) is ready, and in the event thatheadset (20) is not ready, then block (3018) suggests that possiblefailure may have occurred that may need to be addressed immediately. Inthe event that headset (20) is in fact ready and various transmissionshave occurred, then it will be appreciated that HCU (40) may verify thesizes of at least one, if not all transmissions, to avoid transferringstreams that may have significant data sizes that might result intime-consuming stream transmissions.

Other suitable control logic configurations will be apparent to those ofordinary skill in the art in view of the teachings herein.

VI. Exemplary Data Streams

In some versions, headset (20) of ERP system (500) communicates with HCU(40) and/or with a separate computer system. Similarly, HCU (40) maycommunicate with a separate computer system. Such communications mayinclude data regarding the status of headset (20) and/or HCU (40), amongother things.

For example, HCU (40) or headset (20) may transmit information toheadset (20) or a host computer (511), thus providing informationregarding the device status of headset (20). In particular, theinformation may include a serial number associated with headset (20), afirmware version associated with the firmware of headset (20), a batterycharge indicator value, and the self test result flags and errorindicators. While these pieces of information represent the exemplaryinformation to be included, it will be appreciated that more informationmay be included in the device status stream, or in the alternative, onlysome of the pieces of information may be included. In some exemplaryversions, the device status stream may comprise a byte sequence of aparticular length. In some exemplary versions, that length/size may be16 bytes, but any suitable information format may be used as would beapparent to one of ordinary skill in the art in view of the teachingsherein. Furthermore, other suitable device status stream configurationswill be apparent to those of ordinary skill in the art in view of theteachings herein.

As noted elsewhere herein, HCU (40) of ERP system (500) may communicatewith a host computer (511) before, during, and/or after an ERP test. Asession data stream (SDS) may comprise a variety of components as seenin FIG. 22, but in the exemplary version, the session data streamcomprises a descriptor chunk followed by a specified number ofconfiguration chunks. The descriptor chunk may include informationregarding the size of the total SDS. The descriptor chunk may alsoinclude a session global unique identifier comprising a 16-byteidentifier that the host computer (511) may use to associate theattached data with previously stored session parameters. Each of thebytes of SDS may be used to store a piece or several pieces ofinformation. For example, some portions of SDS may be used to storeinformation regarding power failure, audiometry failure, hardwarefailure, or even catastrophic failure which may need to result in theneed to replace headset (20). SDS may be used to store informationregarding audiometry test results. Other suitable information may becontained in SDS as would be apparent to one of ordinary skill in theart in view of the teachings herein.

Furthermore, for configuration descriptor chunks (as seen in FIG. 23)having a number of epoch chunks, a portion of the configurationdescriptor includes information regarding the number of epoch chunks.Other pieces of information may include maximum configuration durationthat was exceeded during configuration, memory exhausted during theconfiguration, power failures that may have occurred duringconfiguration, maximum errors exceeded during configuration, andinformation regarding whether a resting threshold was ever satisfied.

Part of SDS may also include information regarding an epoch descriptorchunk as seen in FIG. 24. Information included in an epoch descriptorchunk may include number of data point chunks in the payload of thedescriptor chunk, the stimulus played during this epoch, an epoch startoffset indicating a time elapsed since the start of the configuration,the number of data points sampled prior to audio stimulus presentation,Epoch descriptor chunk may also include information regarding impedanceof the various recording channels of headset (20) and the number of datapoints sampled prior to button presses including data points sampledduring a pre-trigger delay.

Various other suitable data stream formats will be apparent to those ofordinary skill in the art in view of the teachings herein. It shouldalso be understood that, in some versions, HCU (40) of ERP system (500)only communicates with a host computer (511) before and/or after an ERPtest, such that HCU (40) and the host computer (511) do not communicateduring an ERP test.

As noted elsewhere herein, a host computer (511) may communicate withHCU (40) of ERP system (500) before an ERP test. An exemplary devicesession startup stream (SSS) may be used for such communications. By wayof example only, such communications may include ERP testing protocolsthat are executed on headset (20) solely by HCU (40) after HCU (40) hasreceived the ERP testing protocol or protocols.

The SSS may comprise several packets of information including adescriptor chunk associated with the SSS. The descriptor chunk includesinformation regarding stream length, the session GUID, the number ofconfigurations in SSS, and a total number of audio chunks in SSS. Othersuitable information may be included in descriptor chunk as would beapparent to one of ordinary skill in the art in view of the teachingsherein.

Additionally, SSS includes information regarding a resting threshold, aresting threshold duration, a maximum resting duration, a maximum totalconfiguration duration, a pre-trigger delay duration, a response captureduration, an artifact threshold duration, a maximum number of artifactsfigure, a value for determining whether audiometry testing should beperformed, an inter-configuration delay value, various valuesrepresenting the state of the various electrodes used with headset (20),and any other suitable information as would be apparent to one ofordinary skill in the art in view of the teachings herein. Furthermore,SSS may carry information regarding epoch sequencing chunks. The SSS mayalso contain information regarding audio chunks. In some exemplaryversions, the audio chunk may comprise a raw PCM data file extractedfrom a WAVE file where each audio chunk is organized into a descriptorchunk followed by a payload containing the PCM audio data.

Other suitable startup stream specifications will be apparent to thoseof ordinary skill in the art in view of the teachings herein.

As noted elsewhere herein, some versions of ERP system (500) of thepresent example are run by firmware instead of being run by separatesoftware. For instance, ERP tests may be executed by a microprocessor onHCU (40). By executing tests and providing virtually all other functionsthrough firmware (e.g., on HCU (40)) instead of through software (e.g.,on a separate computer), ERP system (500) may be able to avoid having toexecute tests through an operating system (e.g., Microsoft Windows),which may better facilitate capturing data more precisely, in atime-synched manner (e.g., synchronizing stimulus to patient response),at the time scale of the microprocessor. Such precise and tight timescale capabilities may further facilitate real-time calculations, suchas those associated with in-band impedance matching as describedelsewhere herein. It may also enhance firmware operability to be able toupdate the firmware as needed. The firmware of the present examplecomprises a firmware descriptor chunk and the firmware payload. Thefirmware descriptor chunk may hold information such as the overall sizeof the firemware update stream along with a version number of thefirmware update. It will be appreciated that the version numbers may beformatted or selected to indicate whether the firmware revision isminor, medium sized, or major. The firmware payload may then comprise,for example, a .hex file operable to be loaded into the FLASH core of amicrocontroller used with headset (20). Other file types may be used aswould be apparent to one of ordinary skill in the art in view of theteachings herein. Other firmware uses and update stream specificationswill be apparent to those of ordinary skill in the art in view of theteachings herein.

As noted elsewhere herein, HCU (40) of ERP system (500) may communicatewith a host computer (511) before, during, and/or after an ERP test.Such communications may include transmitting results of an ERP test to ahost computer (511). For instance, HCU (40) may be de-coupled from thehost computer (511) during the ERP test, may store the ERP test resultsas they are acquired, and may be later coupled with the host computer(511) to communicate the ERP test results to the host computer (511)after the ERP test is complete. It should also be understood that HCU(40) may stream the test results in real time to the host computer(511), as the test results are being acquired by HCU (40), during theERP. Such real time communications may be referred to as a “sessionmonitoring stream” (SMS). It will be appreciated that SMS may betransmitted from HCU (40) to the host computer (511) through a wirelessconnection such as Bluetooth connection.

It will be appreciated that SMS may comprise data messages andunsolicited messages. Data message comprises impedance data and sampledata. Impedance messages are operable to be transmitted during only anull action delay period and sample data messages are transmittedcontinually during the pre-trigger delay and response capture durationperiods, which were previously discussed. It will be appreciated thatone sample data message will be transmitted per data point chunk, whichin some instances, may include a frequency of one sample data messageevery 8 ms given a 125 Hz sample cycle. In some exemplary versions datamessages are only transmitted during testing. In contrast, unsolicitedmessages may be sent at any time including at times prior to, during,and after a test is performed. SMS messages comprise a header and apayload. The header includes information regarding the message type aswell as the message size. The SMS payload includes packet descriptorinformation including an impedance message, information regardingwhether epoch has initiated and/or concluded, information regardingstimulus flags, and information regarding the number of electrodescontained in the packet descriptor. Besides the packet descriptor,information regarding button presses on HCU (40), artifacts for variouschannels are used by HCU (40) and the electrode readings of theelectrodes are used with headset (20). Unsolicited messages maycomprise, in contrast, information to be presented to the user in ASCIIcharacter form.

Other suitable ways in which HCU (40) may communicate with a hostcomputer (511) will be apparent to those of ordinary skill in the art inview of the teachings herein.

VII. Exemplary User Interface

An exemplary user interface for an ERP system (500) is provided as FIGS.25-33. The user interface of FIGS. 25-33 may be provided throughsoftware (510) used with HCU (40) and headset (20). This interfaceprovides additional details on the optional components and operationthat may be incorporated into an ERP system (500). It should beunderstood that the components and operability described in the userinterface may be varied in numerous ways. Accordingly, the teachings ofthe user interface should not be viewed as being limited to theparticular context in which they are provided.

FIG. 25 shows an exemplary launcher (300) showing a variety of modulesthat the user may select and execute including a register module (4002)which may be used to register accounts, users, headsets (20), andgroups. It will be appreciated that the register module (4002) may alsobe used to manage user rights. A patient manager module (4004) may beused to enter and review patient information regarding personalinformation and medical information. A protocol editor module (4006) maybe used define any paradigms and/or parameters for ERP tests. A testadministration module (4008) may be used to select the patients to betested and selected. Test admin module (4008) may also be used todownload tests to headset (20), monitor currently running tests, andupload test results to database (310). A viewer module (4010) may beused to view and evaluate test results of an ERP test that has beenperformed. A classifier module (4012) may be operable to classifyresults from any previously performed ERP tests. Finally, a web module(4014) may be used to access the Internet, while the logout module(4016) is operable to simply log the user out of launcher (300).

FIG. 26 shows an exemplary account registration interface form (4018),which may be launched by the activation of register module (4002),allowing a user to input information in relation to the user account. Itwill be appreciated that in some instances, a single account out ofmultiple accounts may function as a primary account for contact andcorrespondence with respect to a group of accounts. FIG. 27 showsheadset registration form (4020) used to register headset (20), whichmay also be launched by the activation of register module (4002).Headset registration form (4020) is operable to accept a serial number,name for registrant name, firmware version, and any other suitableinformation regarding headset (20) as would be apparent to one ofordinary skill in the art in view of the teachings herein. FIG. 28 showsan exemplary user registration form (4022), which may also be launchedby the activation of register module (4002), where a user may enterpersonal user information as well as set the user rights of the user.FIG. 29 shows an exemplary patient manager panel (4024), which may belaunched by the activation of patient register module (4004), operableto show patient search information including personal information andany ERP test scheduled or ordered. Patient manager panel (4024) may alsoinclude relevant information regarding the patient's medical history.Patients may be searched using patient manager panel (4024).

FIG. 30 shows patient manager panel (4024) as a new ERP test is beingordered, which may be launched by the activation of patient registermodule (4004). When ordering an ERP test, it will be appreciated thatthe protocol, date, account for performing the test, the orderingindividual, and any relevant notes may be entered. FIG. 31 shows anexemplary test administration panel (4026), which may be launched by theactivation of test administration module (4008), and used once it hasbeen determined that a test will be executed. Test administration panel(4026) may be operable to allow a user to select which headset (20) willbe used along with providing information regarding headset (20). Theprovided information may include, but is not limited to, the serialnumber of headset (20), the registrant of headset (20), the firmwareversion of headset (20), and the self test and battery statuses ofheadset (20). Other relevant information may be included as would beapparent to one of ordinary skill in the art in view of the teachingsherein. FIG. 32 shows a test administration panel search where ordersfor ERP tests are searched, which may also be launched by the activationof test administration module (4008). Thereafter, the user may select aparticular test protocol and download the test protocol to headset (20).Once downloaded to headset (20), the test may be performed and FIG. 33shows a monitoring panel (4028), also launched by the activation of testadministration module (4008), where various aspects of the ERP test maybe monitored including impedance, stimuli, artifacts, button presses, orany other suitable aspects as would be apparent to one of ordinary skillin the art in view of the teachings herein. In some exemplary versions,monitoring panel (4028) may be used to run a test run to ensure thatsensors and other relevant components are working properly. After thetest run, any collected data may be cleared and the real test may berestarted, which would include recording data, etc.

VIII. Exemplary Impedance Checking Protocol

In some versions, ERP system (500) is configured to measure impedance ateach electrode (100) in an “in-band” fashion. In other words, ERP system(500) is configured to measure impedance along the same channel that isused to sense ERP/EEG responses. Since impedance is frequency dependant,measuring impedance in an in-band fashion (e.g., at the same frequencyas the ERP/EEG measurements) may maximize the accuracy of the impedancemeasurements. In some exemplary versions, headset (20) is operable toexecute an impedance checking protocol, for example, as shown in blocks(748, 750, 752, 754) of FIGS. 13A-13B. For instance, block (750) isoperable to perform baseline impedance measurements at the start of aconfiguration for headset (20). In one merely exemplary version, thefollowing actions may be taken for taking baseline measurements. Headset(20) is operable to enable an individual switch and a REF switch.Furthermore headset (20) may be operable to disable and/or turn off CAL(active electrode) and REF (reference electrode) tones. An amplifierwithin each electrode module (100) may be reset as many as four timeswhere a delay of up to 100 ms between each reset. Thereafter, CAL andREF reference tones may be enabled. In some exemplary versions, a delaythereafter of as many as 1000 ms may be inserted, but any suitable delaymay be inserted as would be apparent to one of ordinary skill in the artin view of the teachings herein. In the present example, thirty-two orany other suitable number of samples may be taken as would be apparentto one of ordinary skill in the art in view of the teachings herein. Allthe switches may thereafter be opened as would be apparent to one ofordinary skill in the art in view of the teachings herein. In thepresent example, headset (20) may comprise as many as six channels forcommunicating information, and the above actions may be repeated for allsix channels. In some exemplary versions, after all six channels aresampled, CAL and REF tones may be disabled and amplifiers may be resetas many as four times. A delay may also be introduced after the initialsampling, which may last as long as 2000 ms. A DSP algorithm for the sixchannels may be implemented at 27.7 Hz and for a reference channel maybe implemented at 13.5 Hz, which will be described in further detailbelow. The voltage response from the various channels of headset (20)may be recorded and may thereafter be saved as V#b, which may benumbered: V1b, V2b, V3b, V4b, V5b, V6b, and Vrb for the referencechannel. In the event that more channels are used with headset (20),then they may be assigned additional numbers.

A period of null-action for headset (20) may follow wherein measurementsare still taken from the six channels of headset (20). During thisnull-action period, CAL and REF tones may be enabled. The amplifier maybe reset a single time and may wait for a time period of 100 ms, but anysuitable waiting time may be used as would be apparent to one ofordinary skill in the art. Thirty-two or any other suitable number ofsamples may be captured from each of the six channels. A DSP algorithmmay be used for all 6 channels at 27.7 Hz and a corresponding algorithmmay be used for a reference channel and/or channel 1 at 13.5 Hz, whichwill be described below. The voltage response from the channels may berecorded as V#z, which may be numbered: V1z, V2z, V3z, V4z, V5z V6z, andVrz for the reference channel. Thereafter, CAL and REF tones may bedisabled and/or turned off.

Regarding the DSP algorithms, for the 27.7 Hz samples, an I value may becomputed with the following formula:

$\begin{matrix}{I = \frac{\left( {{S\; 1} + {S\; 2}} \right) - \left( {{S\; 3} + {S\; 4}} \right) + {\left( {{S\; 5} + {S\; 6}} \right)\mspace{14mu}\ldots}}{16}} & (1)\end{matrix}$

A Q value may be computed with the following formula:

$\begin{matrix}{Q = \frac{{{- S}\; 1} + \left( {{S\; 2} + {S\; 3}} \right) - \left( {{S\; 4} + {S\; 5}} \right) + {\left( {{S\; 6} + {S\; 7}} \right)\mspace{14mu}\ldots}\mspace{14mu} - \left( {S\; 32} \right)}{16}} & (2)\end{matrix}$

I and Q may be used in the following formula to generate a Vac valuewhich will represent V# where # corresponds to the various channels:

$\begin{matrix}{V_{ac} = {{I} + {Q} - \frac{1.17*{I}*{Q}}{{I} + {Q}}}} & (3)\end{matrix}$

For the 13.5 Hz samples, an/value may be computed with the followingformula:

$\begin{matrix}{I = \frac{\left( {{S\; 1} + {S\; 2} + {S\; 3} + {S\; 4}} \right) - \left( {{S\; 5} + {S\; 6} + {S\; 7} + {S\; 8}} \right) + \left( {{S\; 9} + {S\; 10\mspace{14mu}\ldots}} \right)}{16}} & (4)\end{matrix}$

A Q value may be computed with the following formula:

$\begin{matrix}{Q = \frac{\begin{matrix}{{- \left( {{S\; 1} + {S\; 2}} \right)} + \left( {{S\; 3} + {S\; 4} + {S\; 5} + {S\; 6}} \right) -} \\{\left( {{S\; 7} + {S\; 8}\; + {S\; 9} + {S\; 10}} \right) + \left( {{S\; 11} + \ldots - \left( {{S\; 31} + {S\; 32}} \right)} \right)}\end{matrix}}{16}} & (5)\end{matrix}$

I and Q may be used in the following formula to generate a Vac valuewhich will represent V# where # corresponds to the various channels:

$\begin{matrix}{V_{ac} = {{I} + {Q} - \frac{1.17*{I}*{Q}}{{I} + {Q}}}} & (6)\end{matrix}$

Once the various voltage responses as calculated above are recorded, theimpedance of the active electrodes of headset (20) may be calculated tobe:

$\begin{matrix}{{Z{\#\lbrack{ohms}\rbrack}} = {2600\left( {\frac{V\# z}{V\# b} - 2} \right)}} & (7)\end{matrix}$

The impedance of the reference electrodes may be calculated to be:

$\begin{matrix}{{Z\;{{ref}\lbrack{ohms}\rbrack}} = {2600\left( {\frac{Vrz}{Vrb} - 2} \right)}} & (8)\end{matrix}$

In the exemplary version, the channel frequencies of 27.7 Hz and 13.5 Hzare used, but it will be appreciated that any suitable channel frequencymay be used as would be apparent to one of ordinary skill in the art inview of the teachings herein. It will be appreciated that measuring andcalculating impedance in an in-band fashion allows impedance to bemeasured at the same frequency as ERP/EEG measurements. In someversions, it may not be physically possible to measure impedance andERP/EEG signals at literally the same time on the same channel.Therefore, a switching protocol comprising, for example, a multiplexer,may be used to provide near-real time measurement of impedance andERP/EEG signals at the same frequency along the same channel.

In some versions, in-band impedance is measured before an ERP testbegins. Such initial impedance measurements may serve as a baseline forfurther impedance measurements that are performed during the ERP test(e.g., between consecutive epoch sets, etc.). For instance, in versionswhere in-band impedance measurements are taken between consecutive epochsets during an ERP test, the system may compare the impedance levels toa predetermined threshold. If the impedance levels exceed the thresholdat this stage (e.g., indicating loss of sufficient contact betweenelectrode sensor and test subject, etc.), the test may be automaticallypaused and the system may prompt the test administrator to takecorrective action. By way of example only, such a prompt may bedisplayed on a HCU (40) that is being held by the test subject or thetest administrator; may be displayed on the client application beingviewed by the test administrator on a separate computer; and/or may beotherwise provided.

Having shown and described various embodiments of the present invention,further adaptations of the methods and systems described herein may beaccomplished by appropriate modifications by one of ordinary skill inthe art without departing from the scope of the present invention.Several of such potential modifications have been mentioned, and otherswill be apparent to those skilled in the art. For instance, theexamples, embodiments, geometrics, materials, dimensions, ratios, steps,and the like discussed above are illustrative and are not required.Accordingly, the scope of the present invention should be considered interms of any claims that may be presented and is understood not to belimited to the details of structure and operation shown and described inthe specification and drawings.

I claim:
 1. An apparatus comprising: (a) a headset comprising aplurality of electrodes operable to measure evoked response potential(ERP) readings, wherein the headset is configured to be positionable ona test subject; (b) a control unit in communication with the headset,wherein the control unit is configured to store an ERP test protocol,wherein the control unit is configured to administer an ERP test throughthe headset, wherein the control unit is further configured toadminister an impedance test, wherein the impedance test is operable tomeasure the real-time impedance of the electrodes of the headset duringexecution of an ERP test on the test subject, wherein the control unitis operable to process the impedance of the electrodes; and (c) a signalamplifier; wherein the control unit and headset are configured to: (i)execute the ERP test through a first set of channels and receive ERPreadings at a first frequency, (ii) execute the impedance test throughthe same first set of channels, in band with the executed ERP test, atthe first frequency, wherein the impedance test comprises instructionsthat when executed cause the control unit and headset to: (A) obtain abaseline impedance measurement, (B) generate a baseline impedance valuefrom the baseline impedance measurement, (C) obtain a set of activeimpedance measurements during each null-action duration by: (1) enablingan active electrode tone and a reference electrode tone, (2) resettingthe signal amplifier, (3) capturing a set of samples from the first setof channels, (4) applying a first DSP algorithm to a first portion ofthe set of samples and applying a second DSP algorithm to a secondportion of the set of samples, and (5) disabling the active electrodetone and the reference electrode tone, and (D) generate a set ofimpedance values based upon the set of active impedance measurements,(iii) automatically pause the ERP test in response to an impedance valueof the set of impedance values, the impedance value exceeding an initialimpedance measurement, and (iv) display information identifying anelectrode whose measured impedance exceeds the initial impedancemeasurement; and wherein generating a set of impedance values based uponthe set of active impedance measurements comprises instructions thatwhen executed cause the control unit and headset to: (A) computeimpedance for an active electrode using the equation${{Z{\#\lbrack{ohms}\rbrack}} = {2600\left( {\frac{V\#\; z}{V\;\#\; b} - 2} \right)}},$where Z is an impedance value, V#z is a set of voltage values from theset of active impedance measurements, and V#b is a set of voltage valuesfrom a baseline impedance measurement, and (B) compute impedance for areference electrode using the equation${{{Zref}\lbrack{ohms}\rbrack} = {2600\left( {\frac{Vrz}{Vrb} - 2} \right)}},$where Z is an impedance value, Vrz is a reference voltage value from theset of active impedance measurements, and Vrb is a reference voltagevalue from a baseline impedance measurement.
 2. The apparatus of claim1, wherein the control unit is configured to administer an audiometrytest.
 3. The apparatus of claim 1, wherein the control unit isconfigured to operate the impedance test at approximately 27.7 Hz with areference channel operating at approximately 13.5 Hz.
 4. The apparatusof claim 3, wherein: (a) the first DSP algorithm is for the impedancetest at approximately 27.7 Hz, the first algorithm calculating${V_{a\; c} = {{I} + {Q} - \frac{1.17*{I}*{Q}}{{I} + {Q}}}},{where}$${I = \frac{\left( {{S\; 1} + {S\; 2}} \right) - \left( {{S\; 3} + {S\; 4}} \right) + {\left( {{S\; 5} + {S\; 6}} \right)\mspace{14mu}\ldots}}{16}},{Q = \frac{{{- S}\; 1} + \left( {{S\; 2} + {S\; 3}} \right) - \left( {{S\; 4} + {S\; 5}} \right) + {\left( {{S\; 6} + {S\; 7}} \right)\mspace{14mu}\ldots} - \left( {S\; 32} \right)}{16}},$each S is a sample of the set of samples, and V_(ac) is the calculatedvalue for each channel, and (b) the second DSP algorithm is for thereference channel at approximately 13.5 Hz, the second algorithmcalculating${V_{a\; c} = {{I} + {Q} - \frac{1.17*{I}*{Q}}{{I} + {Q}}}},{where}$${I = \frac{\left( {{S\; 1} + {S\; 2} + {S\; 3} + {S\; 4}} \right) - \left( {{S\; 5} + {S\; 6} + {S\; 7} + {S\; 8}} \right) + \left( {{S\; 9} + {S\; 10\mspace{14mu}\ldots}} \right)}{16}},{Q = \frac{\begin{matrix}{{- \left( {{S\; 1} + {S\; 2}} \right)} + \left( {{S\; 3} + {S\; 4} + {S\; 5} + {S\; 6}} \right) - \left( {{S\; 7} + {S\; 8} + {S\; 9} + {S\; 10}} \right) +} \\\left( {{S\; 11} + \ldots - \left( {{S\; 31} + {S\; 32}} \right)} \right)\end{matrix}}{16}},$ each S is a sample of the set of samples, andV_(ac) is the calculated value for each channel.
 5. The apparatus ofclaim 1, wherein the control unit is in communication with a hostcomputer.
 6. The apparatus of claim 5, wherein the host computer isoperable to store a plurality of test protocols operable to be sent tothe control unit.
 7. The apparatus of claim 1, wherein the control unitcomprises a handheld unit.
 8. The apparatus of claim 1, wherein thecontrol unit comprises a switching protocol, wherein the control unitwith the switching protocol is operable to take near real-time impedancemeasurements.
 9. The apparatus of claim 1, wherein the control unit isconfigured to store a plurality of test protocols.
 10. The apparatus ofclaim 1, wherein the control unit is configured to store a plurality ofuser preferences.
 11. The apparatus of claim 1, wherein the headsetfurther comprises six channels associated with the electrodes.
 12. Theapparatus of claim 1, wherein the headset comprises at least onemeasuring channel and at least one reference channel.
 13. The apparatusof claim 1, wherein the impedance test further comprises instructionsthat when executed cause the control unit and headset to obtain thebaseline impedance measurement by: (a) disabling the active electrodetone and the reference electrode tone, (b) resetting the signalamplifier four times, (c) enabling the active electrode tone and thereference electrode tone, (d) capturing a set of baseline samples fromthe first set of channels, and (e) applying the first DSP algorithm andthe second DSP algorithm to the set of baseline samples.
 14. A method ofmeasuring evoked response potential (ERP) data and impedance using aheadset and a control unit, wherein the headset comprises a plurality ofelectrodes operable to measure ERP readings of a test subject, whereinthe control unit is operable to administer an ERP test through theheadset, and wherein the control unit is further operable to measureimpedance at the electrodes, the method comprising: (a) providing one ormore stimuli to the test subject through the headset; (b) detecting ERPreadings of the test subject in response to the one or more stimuli,wherein the ERP readings are gathered along a first channel at a firstfrequency using the electrodes; (c) taking a set of active impedancemeasurements at the electrodes, comprising detecting the impedance alongthe first channel at the first frequency; (d) calculating a set ofimpedance values using the equation${{Z{\#\lbrack{ohms}\rbrack}} = {2600\left( {\frac{V\#\; z}{V\;\#\; b} - 2} \right)}},$where Z is an impedance value, V#z is a set of voltage values from theset of active impedance measurements, and V#b is a set of voltage valuesfrom a baseline impedance measurement; (e) calculating a referenceimpedance value using the equation${{{Zref}\lbrack{ohms}\rbrack} = {2600\left( {\frac{Vrz}{Vrb} - 2} \right)}},$where Z is an impedance value, Vrz is a reference voltage value from theset of active impedance measurements, and Vrb is a reference voltagevalue from a baseline impedance measurement; (f) pausing the ERP test inresponse to an impedance value of the set of impedance values exceedinga baseline impedance value; and (g) displaying information identifyingan electrode associated with the impedance value that exceeds thebaseline impedance value.
 15. The method of claim 14, wherein the act ofdetecting ERP readings and the act of detecting impedance are performedsubstantially simultaneously.